Collision cross sections of gas phase DNA ions

Collision cross sections of negative ions of a 28-, 40- and 55-mer of single stranded DNA have been measured by an energy loss method, and compared to collision cross sections of proteins of nearly the same molecular weight-ubiquitin, cytochrome c and apomyoglobin, respectively. The oligonucleotides produce negative charge states in electrospray ionization (ESI) similar to the positive charge states produced by the proteins denatured in solution. Cross sections for deoxynucleotide ions increase with charge state in a manner similar to those of protein ions. However, for a given molecular weight and charge state, the cross sections of the oligodeoxynucleotide ions are about 22% lower than those of the proteins. (C) 2002 Elsevier Science B.V. All rights reserved.